Ive considered buying a TIG welder for versatility, but a MIG seems to be the standard. I plan on taking a few classes on welding...
I like the idea of being able to weld aluminum, but is it worth the extra cost....AARRGh...

TIG is superior in most ways, but it's more expensive. If you don't currently know how to weld, and you only plan to work on cars, MIG is probably easier. DO NOT buy a flux core welder - you won't be happy with the welds it produces.